Commit Message

While I was working on that, I noticed some other oddities:
1) We were using the same function to test type- and value- dependency
of a qualified-id (SCOPE_REF), but the rules in the standard are different.
2) Fixing that exposed a case where we weren't setting the type of a
SCOPE_REF properly.
3) We want to call mark_lvalue_use in convert_nontype_argument if the
parameter is a reference.
Tested x86_64-pc-linux-gnu, applied to trunk.